The Bureau of Industry and Security (BIS) has prepared this outreach publication to provide clarification on the declaration and reporting requirements related to salts of Schedule 2.B(4) chemicals under the Chemical Weapons Convention Regulations (CWCR) (15 CFR 710 et seq.).

As a general rule, salts of Schedule 1, 2, or 3 chemicals as listed in Supplements No. 1 to Parts 712-714 of the CWCR, respectively, are not subject to declaration and reporting requirements unless explicitly identified in the supplements.¹ However, salts of Schedule 2.B(4) precursor chemicals are subject to declaration and reporting, because the description of Schedule 2.B(4) chemicals is broader than for other Schedule 1, 2 or 3 chemicals:

"Chemicals, except those listed in Schedule 1, containing a phosphorus atom to which is bonded one methyl, ethyl, or propyl (normal or iso) group but not to further carbon atoms."

Therefore, any chemical, including a salt, that meets the following five criteria is considered a Schedule 2.B(4) chemical²:

1. it is a "chemical"
2. excludes [chemicals or entries] "listed in Schedule 1;"
3. [contains] a "phosphorus atom;"
4. the "phosphorus atom" is bonded to "one methyl, ethyl, or propyl (normal or iso) group;" and
5. the "phosphorus atom" is not bonded "to further carbon atoms."

For example, the chemical Phosphonic acid, methyl-methyl 3-(trimethoxysilyl) propyl ester (CAS # 67812-17-3) and a salt of this chemical, Phosphonic acid, methyl-, mono[3(trihydroxysilyl)propyl] ester, monosodium salt (CAS # 84962-98-1), are both Schedule 2.B(4) chemicals. Both the chemical and the salt cited meet the definitional criteria for a Schedule 2.B(4) chemical: (1) each is a chemical; (2) each is not a Schedule 1 chemical; (3) each contains a phosphorus atom; (4) in each chemical, the phosphorus atom is bonded to one methyl group and to oxygen on the other three bonds; the phosphorus is not bonded to any other methyl.

¹ For example, the description for Schedule 3.B(17) ("Triethanolamine") does not explicitly include corresponding salts, and therefore corresponding salts are not subject to declaration or reporting requirements. Conversely, the description for Schedule 2.B(12) ("N,N-Dialkyl (Me, Et, n-Pr or i-Pr) aminoethane-2-thiols and corresponding protonated salts") explicitly includes corresponding protonated salts, and therefore these salts are subject to declaration and reporting requirements.
² Schedule 2.B(4) specifically exempts one chemical that meets the five criteria -- Fonofos: O-Ethyl S-phenyl ethylphosphonothiolothionate.